To earn $500 a week, less than the minimum wage and barely enough to support herself and her autistic daughter, she works about 100 hours a week.

Ms Vu and 14 other outworkers came to Canberra on Tuesday to press the case for better protection that will come in the form of government changes to the Fair Work Act.

The Fair Work Amendment (Textile, Clothing and Footwear Industry) Bill 2011 aims to extend the operation of most provisions of the Act to contract outworkers in the textile, clothing and footwear industry.

It also provides them with a mechanism to enable outworkers to recover unpaid amounts up the supply chain.

Australian Greens MP Adam Bandt, a lawyer who fought for the rights of low-paid workers before entering parliament, said it was not uncommon for shirts that were sold for $200 in Melbourne's Bourke Street Mall to be made by people who received just $2.

"What is so amazing is that for so long, this has been the status quo," he told reporters.

Another woman told AAP she did not dare ask for more than the $5 an hour she averaged, in case it upset her boss.

She believed some of the evening dresses she made sold for around $700 each.

The Textile, Clothing and Footwear Union says poor English language skills contributed to many outworkers feeling unable to negotiate better terms and conditions.

"That compounds their isolation," spokeswoman Shelley Marshall said.

Mr Bandt said tracking the culprits was difficult because a long supply chain was involved.